A 24-Hour Watch To End Dangerous Silent Seizures

Yale-New Haven Developing Round-The-Clock EEG Readings

January 09, 2012|By WILLIAM WEIR, bweir@courant.com, The Hartford Courant

Very subtle seizures in critically ill patients can happen repeatedly and cause permanent brain damage, even as the perfectly still sufferer shows no outward signs of the havoc occurring within.

To reduce the risks of these silent seizures, officials at Yale-New Haven Hospital are planning to keep 24-hour watch on the brains of certain patients.

Electroencephalography (EEG) can monitor a patient's brain activity non-stop and detect these seizures, but most hospitals have only the resources to interpret the EEG readings intermittently. That means it could be hours before action is taken, and as neurologists often say, "time is brain." The faster you can administer treatment, the better chance you have of preventing permanent damage.

To that end, Lawrence Hirsch, director of the epilepsy center at Yale-New Haven Hospital, is developing a "real-time" monitoring program in which trained technologists will watch EEG readings 24 hours a day. The program, which Hirsch hopes to have operating within two years, would be one of the few in the U.S.

Monitoring computer screens 24 hours a day is labor intensive; as a rough estimate, Hirsch said, the Yale program will cost $1 million up front and about $1 million annually.

"The hospital has committed the resources to hiring enough technologists, including ones who are higher-level EEG readers," he said. "It does take some special training."

In 2008, Indiana University Health became the first facility to have a 24-hour monitoring system. Leisha Osburn, director of neurophysiology, said the program has been invaluable.

"There are studies that have shown that patients with brain trauma who also have seizures do worse if we allow them to have these seizures because we're not aware of them," Osburn said. When the on-duty EEG technologist detects a seizure, Osburn said, he or she immediately pages the on-call neurologist, who can look at the readings from any computer and then decide on a course of action.

"That's significant in that it could happen at midnight," she said, adding that without the real-time monitoring, those seizures could "continue until 3 in the afternoon the next day."

The medical community has long known about nonconvulsive seizures, but only in the past decade or so have doctors realized how common they are or how potentially dangerous they can be.

"Somewhere between 15 to 20 percent of people in intensive care units who get EEGs ordered are having seizures on the EEG," said Hirsch, who came to Yale from Columbia University in May. "And the majority of seizures in people in ICUs are non-convulsive."

Ending the seizures sooner, Hirsch said, can help shorten the patient's hospital stay and recovery time, and possibly reduce any permanent damage caused by the seizures.

"You can figure out why they're having seizures if they weren't having them before," he said. Once a seizure has been detected, a neurologist on call can assess the EEG readings and decide the best course of action, which often means changing either the medication or dosage. "You look for the cause and then you can treat it."

The EEG readings — 20 to 23 lines on a computer screen, each representing different activities in the brain — can also detect ischemia, a lack of blood flow to the brain that can lead to strokes.

"You get pretty dramatic EEG changes, well before there's permanent brain injury, so if you see that early enough, you can often intervene and prevent stroke."

How much time a patient has before permanent damage sets in varies greatly. If the decrease in blood flow is gradual, Hirsch said, doctors will have "hours to days, as opposed to a huge stroke, where you have minutes to hours," he said. "Once the blood vessels close off ... every minute counts."